PowerDebug trial version
PowerDebug is a plugin stack upgrade for the built-in debugger, variable watcher, and runtime error stacks. Too many added or upgraded features to list here, but there is a demonstration walkthrough revlet at http://www.ahsoftware.net/PowerTools/PowerDebug/PDDemo.html
This version is fully functional but will present you with nag screens at random intervals to encourage you to buy the "real" version. The full version will also allow you to debug standalone applications on the local machine or cross-platform on any computer on the local subnet.